Weld bead formation by a 10 kW class high power fiber laser on 16 mm thickness carbon steel plate

摘要

In this study, weld characteristics of high power fiber laser welding with a maximum output of 10 kW on thick carbon steel plate were evaluated. Both bead-on-plate and butt joint welding were conducted on SS400 carbon plate of 16 mm thickness under various welding parameters. Acceptable weld profiles with a deep and narrow-weld bead and without apparent defects such as undercut and melt-through can be obtained by single pass process at the optimized welding parameters. Porosity was observed in both cases of partially-and fully-penetrated weld beads. From residual gas analysis results of the porosity, trapping ofAr shielding gas was a main reason for porosity formation in the partially-penetrated weld bead, whereas trapping of infiltrated N_2 gas from Air atmosphere through keyhole opened in the weld pool on the back side and resultant CO gas were major causes in the fully-penetrated weld bead.